Review on Enhance Your Air Quality with Colorfullfe Performance Plus Filter for Holmes AER1 True Filter: 4 Filters and 8 Carbon Filters by Brian Shakey

The original branded blue filter that comes with the unit has less tight vertical pleats, I thought this filter with tighter horizontal pleats would Due to the general compensating nature of the product, but instead of increasing the surface area to allow the machine to breathe easier, it was actually noticeably more difficult to force air through, to the point where an unbearable hiss is heard in silent mode, and not around the Gasket around but still somewhere on the block that the air now flows through. I cleaned the seals, squeezed to see what was leaking (it wasn't), tried both filters, same problem, the high pitched whistling just made the unit unbearable, just a shame because it looks decent otherwise. By removing the filter while the fan is running, you can feel how much more the thing sticks to the device than the factory filter. its own case is somewhere else, but it doesn't fit the Holmes Tower HAP9413.